The present invention relates to an engine controller for controlling an engine operation actuator (for example, a throttle, a fuel injector or the like) to generate an output torque and power in consideration of an actual engine condition (for example, an output torque, an output power (estimated from output torque and engine rotational speed), an intake air mass flow rate, an opening degree of throttle or the like).
JP-A-10-212989 discloses an engine controller in which an operation degree of an engine operation actuator is adjusted in accordance with an actual engine condition and a circumferential condition of the engine.
JP-A-10-238394 discloses how to detect a trouble of throttle.
An object of the present invention is to provide an apparatus (for example, engine) controller with a feed-back control system, in which controller an output of the apparatus is safely controllable when a trouble of an element used for the controller occurs.
In an engine controller for controlling an engine condition adjusting device in an engine in consideration of an actual engine condition measured by an engine condition measuring sensor, comprising, an interface device for generating an input signal corresponding to a desired engine condition, and an instruction signal generator for determining an instruction signal to be input to the engine condition adjusting device for controlling an operation degree of the engine condition adjusting device on the basis of a comparison between the input signal and an actual engine condition signal corresponding to the actual engine condition so that a difference between the desired engine condition and the measured actual engine condition is decreased,
since the instruction signal for controlling the engine condition adjusting device is determined on the basis of the comparison between the input signal and the actual engine condition signal when normalities of the interface device, the engine condition changing device and the engine condition measuring sensor are detected, and is determined on the basis of the input signal while preventing the instruction signal from being determined on the basis of the comparison between the input signal and the actual engine condition signal when an abnormality of at least one of the interface device, the engine condition changing device and the engine condition measuring sensor is detected, a degree of an excessive or uncontrollable engine operation or output caused by the troubled at least one of the interface device, the engine condition changing device and the engine condition measuring sensor is kept small, or an undesirable or uncontrollable engine operation or output is prevented from being enlarged by a multiplicative trouble effect among the interface device, the engine condition changing device and the engine condition measuring sensor by returning to a simple control based on the input signal without the comparison between the input signal and the actual engine condition signal.
The interface device may generate the input signal corresponding to a desired engine output power ordered from an accelerator outside of the engine controller. The instruction signal for controlling the engine condition adjusting device may be determined on the basis of the comparison between the input signal generated by the interface device and the actual engine condition signal when the normalities of the interface device, the engine condition changing device and the engine condition measuring sensor are detected, and is determined on the basis of the input signal corresponding to the desired engine output power ordered from the accelerator while preventing the instruction signal from being determined on the basis of the comparison between the input signal generated by the interface device and the actual engine condition signal when the abnormality of the at least one of the interface device, the engine condition changing device and the engine condition measuring sensor is detected.
The interface device may generate the input signal corresponding to a desired engine output power, a desired engine output torque, a desired injection rate of a fuel to be injected into the engine or a desired mass flow rate of an intake air to be taken into the engine, as the desired engine condition. The input signal corresponding to the desired mass flow rate of the intake air to be taken into the engine may be modified in accordance with a desired air-fuel ratio.
The instruction signal generator may determine the instruction signal for controlling an opening degree of an electrically controlled throttle as the engine condition adjusting device. The instruction signal may be modified in accordance with a desired air-fuel ratio. The instruction signal generator determines the instruction signal for controlling an injection rate of a fuel to be injected into the engine.
The actual engine condition signal may correspond to an actual mass flow rate of an intake air to be taken into the engine, an actual engine output torque or an actual engine output power (which may be estimated from output torque and engine rotational speed). The actual fuel injection rate may be estimated from the actual engine output torque or the actual engine output power per engine rotation. The actual mass flow rate of the intake air to be taken into the engine corresponds to the actual engine output power when the air-fuel ratio is kept at a certain degree, so that the actual engine output power is estimated from the actual mass flow rate of the intake air. The desired injection rate of the fuel to be injected into the engine corresponds to the desired engine output power or torque. The desired injection rate of the fuel per engine combustion cycle or engine output rotational speed corresponds to the desired engine output power per engine combustion cycle or engine output rotational speed, or the desired engine output torque.
The instruction signal for controlling the engine condition adjusting device may be determined on the basis of the comparison between the input signal corresponding to the desired engine output torque and the actual engine condition signal corresponding to the actual engine output torque when a normality of a torque sensor of the engine condition measuring sensor is detected, and be determined on the basis of the input signal corresponding to the desired engine output power (ordered by, for example, an accelerator outside of the controller) while preventing the instruction signal from being determined on the basis of the comparison between the input signal corresponding to the desired engine output torque and the actual engine condition signal corresponding to the actual engine output torque when the abnormality of the engine condition measuring sensor for measuring the actual engine output torque is detected.
The interface device may generate the input signal corresponding to the desired engine output power or torque on the basis of an engine output rotational speed and an instructed engine output power instructed from an accelerator outside of the engine controller.
When at least of the engine condition changing device and the engine condition measuring sensor includes a communication path through which an information is transmitted with respect to the engine controller, the abnormality of the at least one of the engine condition changing device and the engine condition measuring sensor may be the abnormality of the communication path. When a throttle of the engine condition changing device for controlling the mass flow rate of the intake air to be taken into the engine includes at least one sensor for generating an output signal corresponding to an opening degree of the throttle, the abnormality of the engine condition changing device may be an abnormality of the sensor. When the interface device generates the input signal in accordance with an output signal of at least one sensor outside of the engine controller for measuring an operated degree of an accelerator outside of the engine controller, and the operated degree of the accelerator corresponds to an ordered engine output power ordered by the accelerator, the abnormality of the interface device may be an abnormality of the sensor.
The operation degree of the engine condition adjusting device may be an opening degree of the throttle for adjusting the mass flow rate of the intake air to be taken into the engine, or the injection rate of the fuel to be injected into the engine.
At least one of a prevention of forming a lean fuel air mixture, a decrease of an upper limit of an injection rate of a fuel to be injected into the engine, a decrease of an upper limit of an opening degree of a throttle as the engine condition adjusting device, a close of the throttle and a prevention of supplying an electric current to the throttle may be carried out in response to the abnormality of the at least one of the interface device, the engine condition changing device and the engine condition measuring sensor is detected. Which is selected to be carried out from the prevention of forming the lean fuel air mixture, the decrease of the upper limit of the injection rate of the fuel to be injected into the engine, the decrease of the upper limit of the opening degree of the throttle, the close of the throttle and the prevention of supplying the electric current to the throttle may be determined in accordance with a degree of the abnormality of the at least one of the interface device, the engine condition changing device and the engine condition measuring sensor.
The abnormality of the sensor may detected when a magnitude of the output signal of the sensor is in a range other than a predetermined acceptable range. The abnormality of the sensor may be detected when a difference between a plurality of the output signals of the sensors is more than a predetermined acceptable level. The abnormality of the engine condition changing device may be detected when a difference between an actual opening degree of the throttle of the engine condition changing device and a desired opening degree of the throttle is kept more than a predetermined acceptable level for a time period more than a predetermined acceptable time period. The abnormality of the engine condition changing device may be detected when an electric current supplied to an electrically controlled throttle of the engine condition changing device is kept more than a predetermined acceptable level for a time period more than a predetermined acceptable time period. The abnormality of the engine condition measuring sensor may be detected when a magnitude of the actual engine condition signal corresponding to the actual mass flow rate of the intake air to be taken into the engine is in a range other than a predetermined acceptable range. The abnormality of the engine condition measuring sensor may be detected when a difference between the actual engine condition signals which are generated by a plurality of the engine condition measuring sensors and correspond respectively to actual mass flow rates of the intake air to be taken into the engine is more than a predetermined acceptable level. The abnormality of the engine condition measuring sensor may be detected when a difference between the actual mass flow rate of the intake air to be taken into the engine measured by the engine condition measuring sensor and a mass flow rate of the intake air to be taken into the engine estimated from the engine output rotational speed and the opening degree of the throttle of the engine condition changing device is more than a predetermined acceptable level. The abnormality of the engine condition measuring sensor may be detected when a magnitude of the actual engine condition signal corresponding to the actual engine condition is in a range other than a predetermined acceptable range. The abnormality of the engine condition changing device may be detected when a difference between the input signal and the actual engine condition signal is more than a predetermined level.
The desired condition corresponding to the input signal compared to the actual engine condition signal to determined the instruction signal when the normalities of the interface device, the engine condition changing device and the engine condition measuring sensor are detected may be different from the desired condition corresponding to the input signal on the basis of which the instruction signal is determined when the abnormality of the at least one of the interface device, the engine condition changing device and the engine condition measuring sensor is detected. The desired condition corresponding to the input signal compared to the actual engine condition signal to determined the instruction signal when the normalities of the interface device, the engine condition changing device and the engine condition measuring sensor are detected may be equal to the desired condition corresponding to the input signal on the basis of which the instruction signal is determined when the abnormality of the at least one of the interface device, the engine condition changing device and the engine condition measuring sensor is detected.
In a controller for controlling an apparatus condition adjusting device in an apparatus in consideration of an actual apparatus condition measured by an apparatus condition measuring sensor, comprising, an interface device for generating an input signal corresponding to a desired apparatus condition, and an instruction signal generator for determining an instruction signal to be input to the engine condition adjusting device for controlling an operation degree of the apparatus condition adjusting device on the basis of a comparison between the input signal and an actual apparatus condition signal corresponding to the actual apparatus condition so that a difference between the desired apparatus condition and the measured actual apparatus condition is minimized,
since the instruction signal for controlling the apparatus condition adjusting device is determined on the basis of the comparison between the input signal and the actual apparatus condition signal when a normality of at least one of the interface device, the apparatus condition changing device and the apparatus condition measuring sensor is detected, and is determined on the basis of the input signal while preventing the instruction signal from being determined on the basis of the comparison between the input signal and the actual apparatus condition signal when an abnormality of at least one of the interface device, the apparatus condition changing device and the apparatus condition measuring sensor is detected, a degree of an excessive or uncontrollable apparatus operation or output caused by the troubled at least one of the interface device, the apparatus condition changing device and the apparatus condition measuring sensor is kept small, or an undesirable or uncontrollable apparatus operation or output is prevented from being enlarged by a multiplicative trouble effect among the interface device, the apparatus condition changing device and the apparatus condition measuring sensor by returning to a simple control based on the input signal without the comparison between the input signal and the actual apparatus condition signal.